#include<iostream>
using namespace std;
namespace chen {
	int rand = 10;
	int Add(int left, int right)
	{
		return left + right;
	} 
	struct Node
	{
	struct Node* next;
	int val;
	};
}
using namespace chen;
int main()
{
	printf("%d\n",Add(1,2));
	cout << "hello world" << endl;
	return 0;
}